Dayton Daily News

Q: It seems there is an electrical problem in my 1993 Cadillac Deville with 100,000 miles that my local dealer mechanic can’t repair. The trouble didn’t occur until I took the car in for a new water pump, front tires, spark plugs and an oil change. Right after this work, I heard clicking sounds coming from behind the glove compartment, and the digital dash simultaneously started blinking. After three minutes of clicking and blinking, the dash went dark except for the speedometer.

Also, the heater and air conditioning system became stuck in one mode. A dealer technician has replaced both panels on the instrument panel. He also has followed factory- recommended diagnostic charts, but his work has been in vain. Twice after I was told the car was repaired, I drove from the dealer and the dash went dead and the heating air conditioning and ventilation system was stuck on one mode. Now dealer personnel are at a loss. Can you help? C.K., Champaign, Ill.

Do you have any information about these tires that would make me feel good about the tires? Do you think the dealer should compensate me for these tires since the salesperson did not disclose that the run-flats were on the vehicle? Do I have any recourse? S.S., e-mail

A: It’s possible that during some of the engine work, a wire has lost continuity. Perhaps a ground wire needs tightening or there is corrosion interfering with electrical flow. A technician needs to check under the hood for problems. It’s also possible that communications between the control modules in the vehicle are being interrupted by a poor electrical connection. This too could be caused by corrosion or by a loose terminal in a plug. A faulty relay could also cause problems such as these, so a technician should look into this as a possible cause for the trouble. To fix this problem may be as simple as tightening a ground wire, replacing a body control module, installation of a new relay or perhaps more difficult as hunting for a poor connection within a plug.

Look beyond fuel pump

Q: Help! I have a 1994 GMC 2500 conversion van with a 5.7-liter engine and air conditioning. The fuel pump has been replaced three times within a short time. Now after the van has been in storage for the last three months, the fuel pump is going out again. According to the mechanic who is working on the van, the fuel pump is getting power. He replaced the relay, but this did not solve the trouble. At $500 a crack I cannot afford to keep replacing fuel pumps. What else could cause this problem? D.H., e-mail

A: I doubt all three fuel pumps have been faulty. The powertrain control module, oil pressure switch inline, fuse relay and ignition module all play a part in energizing the fuel pump. Once the powertrain control module receives signals from the oil pressure switch and ignition module, the PCM turns on the fuel pump circuit via the inline fuse and relay. A faulty oil pressure switch, ignition module or powertrain control module might be the root of the problem. It’s also possible a faulty connection at any of these devices, including the inline fuse, could impair electrical flow to the pump. Also, if your van is equipped with a theft deterrent system, there may be a problem in the system that impairs the fuel pump. If so, a technician should perform tests to determine faults. If there is an aftermarket system on the vehicle, you might have to remove it to regain proper function of the pump.